intltool.m4 error with OpenBSD sh

On OpenBSD, configure scripts that use intltool.m4 produce this error:

checking for perl... /usr/bin/perl
checking for perl >= 5.8.1... Can't find string terminator '"' anywhere before EOF at -e line 1.

This is specifically due to this line of sh code in intltool.m4:

   IT_PERL_VERSION="`$INTLTOOL_PERL -e \"printf '%vd', $^V\"`"

OpenBSD's /bin/sh normally processes this just fine, but autoconf scripts now enable POSIX mode (set -o posix), which causes these nested quotes to be parsed differently. This may or may not be a bug in OpenBSD's sh, but meanwhile it is easy to avoid this problem by not nesting more quoting levels than necessary. Since there is no word splitting/globbing in variable assignments, this would do just fine:

   IT_PERL_VERSION=`$INTLTOOL_PERL -e "printf '%vd', $^V"`